Bruker Biospin Ag

Roberto Seydoux

Daniel Marek

Oskar Schett

Beat Grossniklaus

Hansjoerg Tschirky

Hansjörg Tschirky

Michael Warden

A tubular capacitor with variable capacitance, including a cylindrical tube () of dielectric material, a metallic outer electrode () which surrounds the cylindrical tube (), and an inner electrode which can axially move in the inner bore () of the cylindrical tube () and which abuts the inner bore (), wherein the inner electrode includes a metallic rod ('), located in the inner bore () of the cylindrical tube (), using a rod () of dielectric material. The inventive tubular capacitor has an increased dielectric strength and improves the resolution of NMR spectrometers.

Tubular capacitor with variable capacitance and dielectrically elongated inner electrode for NMR applications

A device for transporting an elongated sample tube ( ) into the measuring chamber ( ) of an NMR magnet system comprising a spinner which has an axial through-bore through which the sample tube can be inserted, transported together with the spinner on an air cushion into the measuring chamber, and positioned therein relative to the vertical axis of the NMR receiver coil system ( ) is characterized by a mounting sleeve ( ) which is disposed in a collar-like manner radially around the sample tube such that it cannot slip and which, in the operating position of the sample tube, flatly abuts with one end face thereof on a horizontal stop surface ( ) in the bottom region inside a two-stage axial bore ( ) of the spinner ( ), wherein the inner diameter of the bore ( ), in a first stage in the upper region, is larger than the outer diameter of the mounting sleeve, and the inner diameter of a second stage, in the bottom region of the spinner, is smaller than the outer diameter of the mounting sleeve but larger than the outer diameter of the sample tube. This permits modification of a transport device for NMR measuring capillaries using simple technical means such that it is less sensitive than the conventional devices to curtail breakage of glass.

Device for the transport and exact positioning of a sample tube in a high-resolution NMR spectrometer

A device for centering an elongated sample tube ( ), filled with a measuring substance, relative to the vertical axis of an NMR receiver coil system ( ) which is rigidly mounted in a support device, is characterized in that at least two centering devices ( ) are provided which are separated from each other in an axial direction of the receiver coil axis and act on the sample tube in a radial direction only, one of which is disposed above and the other below the NMR receiver coil system, and at least one positioning devices ( ) which acts on the sample tube in an exclusively axial direction and which can be located either below or above the NMR receiver coil system, wherein the exclusively radially acting centering devices are rigidly connected to the support device for mounting the NMR receiver coil system. This considerably increases the centering accuracy compared to known devices with simple technical devices to obtain optimum results even for measuring capillary sample tubes which pose the highest requirements in centering accuracy.

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Volketswil, Switzerland

Roberto Seydoux